The portable solar cooker FV-04 works by trapping the heat generated by the black glass within the transparent jar. The glass jar (600 ml.) is sealed to protect the food from the plastic smell and avoid steam entering the transparent jar. The external reflectors increases the quantity of solar rays that reach the black jar and act as a container when the cooker is closed. The clamps are used to angle the reflector towards the sun. Food or water needs to be placed in water in the cooker before placing it in the sun to avoid warping the PET bottle. The transparent jar can be made of glass but this doubles the overall weight of the cooker. The cooker can reach temperatures of up to 80 - 90 ºC.